Process and apparatus for sulphurizing paper board



Au 29, 1933. R WILLAUER 1,924,142

PROCESS AND APPARATUS FOR SULPHURIZING PAPER BOARD Filed Feb. 1. 1930 Q I ZHYEfi/AIJF" lflaZZa'am E Millauerr Patented Aug. 29, 1933 UNITED STATES PATENT OFFICE William R. Willauer, Philadelphia,

Pa., assignor to Marathon Paper Mills Company, Rothschild, Wis.,

a Corporation of Wisconsin Application February 1, 1930. Serial No. 125,227

11 Claim.

This invention relates to a process for 1mpregnating fibrous material such as fiber board, cloth and the like, preferably in the form of a web, with sulphur, and to an apparatus for carrying out such a process.

The processes generally employed for this purpose are unable to control the distribution and content of the sulphur in the impregnated sheet without causing the formation of blow holes, blisters or other defects which decrease the value of the impregnated sheet.

I have now found that I can impregnate webs or sheets of fibrous material with sulphur and definitely control the distribution and content of the sulphur without the formation of blow holes,

by causing the impregnablisters and the like, tion to take place under pressure.

It is accordingly an object of this invention to provide a process for impregnating fibrous sheets with sulphur.

It is a further object of this invention to provide a pressure apparatus for impregnating fibrous sheets with sulphur.

Other and further important objects of this invention will become apparent from the following description and appended claims.

Referring now to the drawing which discloses a. preferred embodiment of my invention, the figure there disclosed illustrates a longitudinal section through an impregnating machine, and a reel of fiber board for impregnation therein.

As shown on the drawing:

The impregnating machine indicated generally by the reference numeral 1 comprises an elongated, metallic tank or container 2 containing a molten bath of sulphur indicated by the letter S. The tank 2 is formed of or lined with metal resistant to attack by molten sulphur. A portion of the top of the tank is closed by a fixed cover plate 3. Around the inner periphery of plate 3 is a ledge 4, which supports a removable dome-shaped double-walled cover 5, having an outer sectional wall 6 and an inner wall 7 between which is a dead air or insulating space 8. The sections of the outer cover-wall 6 are joined by hinged members as at 9. Conventional latch members 10 secured toplate 3 maintains the cover in place on the container 2.

A web, sheet or the like, 11, of the fibrous material to be treated is made to pass at regulated speed through the sulphur bath S. In order to regulate the tension of the web in its passage through the tank, a plurality of submerged rolls 12 are suspended from the cover by means of shafts 13 carried by adjustable bearing blocks 14. Each bearing block 14 is slidably mounted in guides 16 and for this purpose is provided on opposite faces thereof with grooves which receive the guides 16 formed on brackets 15-. Portions of each supporting bracket project through the inner cover wall 7 from which the brackets are supported by means of straps or hands 20 or similar conventional supporting means. Each bracket 15 has a base 17 connected to the lower ends of guides 16 and an end portion 18 connected to the upper ends of said guidw. The connecting end 18 is provided near its center with a threaded hub 21 in which is positioned a screw 22 fastened at its lower end to a bearing block 14. Screw 22 projects through the cover 5 and is provided externally of said cover with a hand wheel 23 by means of which it maybe rotated to raise or lower the bearing block 14. As shown on the drawing, three adjustable rollers 12 are provided, the supports for the outer rolls being inclined to cause the rolls to makeproper contact with the web 11.

The web 11 enters the tank 2 through a slot 24 in cover plate 3 at one end of the tank and leaves through a similar slot 25 in the opposite end of the tank. The inlet slot 24 is partially I closed by means of a pair of doctor plates 26 secured in a recess 27 in the wall of plate 3 surrounding slot 24. A pair of shafts 28, one above and the other below plate 3, carry a pair of pres- 8 sure sealing rolls 29. Said shafts 28 are so positioned that the rolls project into that portion of the inlet opening left uncovered by doctor plates 26 and by contacting with each other and the inner periphery of the doctor plates 26 seal the inlet opening. Similar means including pressure rolls 29a are provided at the opposite end of the tank for sealing the exit slot 25. g

The web 11 passes between the sealing rolls at each end of the tank. Said rolls are power driven and constitute the means for drawing the web through the impregnating tank.

Electrical resistance or heating elements 41 are inserted in rolls 29a'in order to heat these rolls to iron and calender the web as it passes between said rolls and also to prevent the solidification of sulphur on said rolls. The heating elements 41 which are insulated from said rolls are connected to a current source by means of collecting rings or brushes (not shown) which make contact with the heating elements 41 during their rotation about the shafts of rolls 29a.

Before the web enters the impregnating tank,

it is necessary to preheat the web to dry the same.

This is accomplished by means of a preheating -'order to provide a regular pa vtion on the tank, the rolls 2 i chamber 30 consisting of a housing 3011 having an open end positioned over the sealing rolls in the web inlet 24. Said housing is provided with an aperture 32 in the top thereof for the web 11 and for the escape of the vapors driven from the web 11. Steam coils 31 are arranged in the housing on both sides of the path of travel of the web 11 for supplying heat to the web.

After leaving the tank the web 11 passes through a heat extractor 33, comprising a housing 34 arranged over the web exit opening 25, said housing 34 being similar to but smaller than honeing 30a of the preheating chamber. In order that access may be readily had to said rolls, the housing is formed with a sectional side wall 35, the sections being hinged together at 36. By this arrangement; the part of wall 35 covering the sealing rolls may be swung upwardly to expose said sealing rolls. Refrigerating means may be provided for cooling the housing 34 but as a general rule this is not necessary:. An opening 37 in the top of the housing v34 provides an exit for the web 11. It will be noted that housing 29 and 34 are both inclined fro the horizontal in h of travel for the web 11.

The web 11 is fed to the impregnating tank from a reel 38 mounted externally of the impregnating machine.

The molten sulphur S in the tank 2 is placed under pressure by air forced into the space between the upper surface of the bath and the tank cover through pipe 39, any conventional means being used to inject the air. Due to the tight joint maintained by the sealing rolls, the pressure in the tank is maintained practically constant throughout the operation of the'process.

In order to maintain the molten sulphur bath at the proper temperature, steam coils 40 or similar heating means are arranged in the bottom of tank 2.

The operation of my device is as follows:

The web 11 is threaded through the preheat ing chamber, sealing rolls 29, tank 2, sealing rolls 29a and heat extractor 31. During this operation, the cover 5 willbe in raised position, the web taking the position indicated in dotted lines on the drawing. The cover 5 is placed in posi- 12 being then adjusted by turning the hand wheels to properly tension web ll. Air is then forced into the tank to place the molten sulphur under ressure. If necessary, heat may be supplied to bring the sulphur to the proper temperature. When the proper conditions havebeen reached power is applied to the sealing rolls 29 and 29a, thus causing the web 11 'to progress through the molten sulphur bath. The speed of travel of the web through the bath is carefully regulated in order that the required impregnation may be obtained.

While my process and apparatus may be operated under diiferent conditions of operation, I have found that the best results will be obtained by observing the following conditions: The sulphur bath should be maintained at a temperature of from about 260 to 280 degress Fahrenheit under a pressure of from about 20 to pounds per square inch. The speed or the traveling web'may be so varied that the web is subjected to the action of the sulphur bath for a period or from about 5 to 60 seconds. By observing these conditions, I have been able to impregnate a board or web of fibrous material with a content of sulphur ranging from about 170 to 182 per cent by weight of the web, the sulphur in each case being equally distributed through the fibers, the impregnated web also being free of blow holes, blisters and the like.

' While I have disclosed a preferred embodiment of my invention, it is to be understood that I do not purpose to be limited thereto as various details of construction and operation may be varied without departing from the scope or the invention disclosed.

I claim as my invention:

1. The process of impregnating fibrous material with sulphur, which comprises subjecting the fibrous material to a bath of molten sulphur under a pressure of from about 20 to 80 pounds per square inch.

2. The process of impregnating fibrous material with sulphur, which comprises drying the fibrous material, subjecting the same to a molten bath of sulphur under a pressure of from about 20 to 80 pounds per square inch and cooling the impregnated material.

3. The process of impregnating fibrous material with sulphur, which comprises subjecting the material to a fused bath of sulphur under a pressure of from about 20 to 80 pounds per square inch and at a temperature of from about 260 to 280 F.

4. The process of impregnating fibrous material with sulphur, which comprises drying the 10p fibrous material, continuously subjecting the same in the form of a traveling sheet to a molten bath of sulphur under apressure of from about 20 to 80 pounds per square inch and at a temperature of from about 260 to 280 F. and coolin the sheet as it leaves the sulphur bath.

5. Apparatus for impregnating fibrous material with sulphur, comprising a closed tank for a bath of molten sulphur, means for placing said bath under pressure, means for feeding a continuous sheet of fibrous material through said tank, adjustable rolls suspended in said tank for regulating the tension of said sheet, an inlet for said sheet at one end of said tank, a substantially closed housing, through which said sheet passes, over said inlet, sealing rolls in said inlet for maintaining the pressure in said tank, and means in said housing for heating said sheet during its passage therethrough.

6. Apparatus for impregnating fibrous material with sulphur, comprising a tank for a bathof molten sulphur, means for placing said bath under pressure, means for passing a continuous sheet of fibrous material through said tank, an inlet for said sheet at the one end of said 0 tank, an outlet for said sheet at the other end of said tank, means for tensioning the sheet during its progress through the tank, means for sealing the sheet inlet and outlet to maintain the pressure in said tank, means at the inlet end of said 5 tank for drying said sheet and means at the exit end of said tank for cooling said sheet.

7.'Apparatus for impregnating fibrous material with sulphur, comprising a tank for a molten sulphur bath, means for placing said bath under pressure, means for continuously feeding a sheet of fibrous material through said tank, a plurality of sheet tensioning rolls adjustably suspended in said tank, an inlet for said sheet at.

one end of said tank, an exit for said sheet at 1 sealing rolls and means for heating said sheet, and a heat extractor for said sheet comprising a substantially closed housing over said exit sealing rolls.

8. A device for impregnating a sheet of fibrous material with sulphur, comprising a tank for a molten bath of sulphur having an open top, a double walled cover closing said top, means for placing said tank under pressure, adjustable rolls suspended from said cover, an inlet in one end of said tank for a continuous web of fibrous material and exit at the opposite end of said tank for said web, pressure sealing rolls projecting into said inlet and outlet for closing the same to maintain the pressure in said tank, means for driving said sealing rolls for drawing said web through said tank and in contact with the adjustable rolls therein whereby to regulate the tension of said web, a substantially closed housing over said web inlet through which said web is adapted to pass, means in said housing for drying said web, and a substantially closed housing over said web exit for cooling the web as it leaves said tank.

let and outlet comprising" doctor plates and sealing rolls positioned so as to contact in said inlet and outlet, and means for driving said sealing rolls to cause the web to move through said tank, said sealing rolls being provided with electrical means for heating said rolls whereby to iron said web and prevent solidification of sulphur on said rolls.

WILLIAM R. WILLAUER. 

